Incidence of Vascular Complications Associated with Anterior Thoracic Instrumentation for Adolescent Idiopathic Scoliosis

·(a – DePuy AcroMed Corp.)

Purpose: Placement of anterior thoracic instrumentation for correction of adolescent idiopathic scoliosis (AIS) is done in proximity to the major vessels of the thorax (aorta, vena cava, azygos vein). This prospective study reviews the incidence of vascular injury perioperatively and postoperatively in a multicenter group of patients followed for a minimum of two years.

Methods: 117 patients with AIS underwent anterior thoracic instrumentation and fusion either through an open thoracotomy (109 patients) or thoracoscopic (8) technique. Spinal screws were placed transversely in each vertebra spanning the Cobb measurement of the major thoracic curve, limit T4-L1. Prior to screw insertion, segmental vessels were ligated and the pleura with the major vessels retracted into the concavity of the curve. Sponges and/or retractors were placed to protect the major vessels during screw insertion. All screws were inserted bicortically, with a pointed tip and one to two threads protruding through the concave cortex. No guide pins were used, but a tap was used prior to the thoracoscopic screw insertion. Screw length was checked by palpation, x-ray, or both. Hemostasis was satisfactory prior to chest closure, with closure of the pleura over the instrumentation done in all but the thoracoscopic cases. Postoperative hemoglobin and hematocrit, along with chest tube drainage, were monitored for three days for evidence of intrathoracic hemorrhage. All patients were followed prospectively for a minimum of two years, and any reoperations were noted.

Results: 117 patients had 819 screws placed (average 7 screws per patient), one screw per instrumented vertebra. Average age of the patient was 14.5 years, the ratio of female to male was 4:1. 109 patients were done with an open double or single thoracotomy technique, and 8 patients through a video-assisted thoracoscopy technique. There was one reoperation for a thoracic duct tear but none for undetected perioperative or delayed postoperative vascular injuries. There were no postoperative unexplained drops in hemoglobin/hematocrit or unexplained increased bloody chest tube drainage. In the two year follow-up period, there were no reoperations for hemorrhage into the chest, and no evidence of vascular injury.

Conclusions: While anterior thoracic instrumentation for idiopathic thoracic scoliosis is placed in proximity to the major vessels of the thorax, the incidence of perioperative and postoperative vascular complications in this series was zero.

· If noted, the author indicates something of value received. The codes are identified as: a-research or institutional support; b-miscellaneous funding; c-royalties; d-stock options.